JPH04116405A - Automatic plate-thickness measuring apparatus - Google Patents

Abstract

PURPOSE:To enable calibration with a simple, low-cost, compact apparatus for the entire width in multipoint measurements by obtaining a reference distance based on the outputs of optical displacement gages and the thickness of a calibrating plate at the time of calibration. CONSTITUTION:An operating and controlling part 34 controls a linear motor 32 and drives optical displacement gages 18 to the right and left. For example, the operating and controlling part 34 operates a reference distance Lo based on the outputs l1 and l2 of the optical displacement gages 18 at every time when the optical displacement gages 18 are moved by the specified amounts. The obtained reference distance Lo is made to correspond to the coordinates of the position of the optical displacement gages 18 and stored in a memory 36 as a calibrating table. The calibrating table is prepared for every pair of the displacement gage 18. The calibrating table is used as the reference when the plate thickness of a body under measurement is measured. Namely, the operating and controlling part 34 obtains the reference distance Lo which is used in operation of a plate thickness L in reference to the calibrating table that is deployed on the memory 36. As a result, the plate thickness L fits into the position in the direction of the width of the conveying line. The plate thickness L is obtained based on recently measured reference distance Lo.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic plate thickness measuring device that automatically measures the plate thickness of an object to be measured transported by a transport line in a non-contact manner by reflecting a light beam. .

[Prior Art] An automatic plate thickness measuring device that automatically measures the plate thickness of an object to be measured transported by a transport line using an optical displacement meter has been conventionally known.

The device used in the past is a one-point measurement device using a so-called C-shaped frame, and is mainly used to measure objects with a constant width, that is, objects with a fixed width. It was getting worse.

When performing automatic plate thickness measurement, it is necessary to perform calibration periodically. This corrects errors caused by aging of the optical displacement meter (electrical correction) and also corrects mechanical distortion (mechanical correction) to maintain reliability and ensure accurate plate thickness measurements. It is something.

[Problems to be Solved by the Invention] However, there are various problems in such proofreading, and solutions to these problems are desired.

Specifically, for example, there are problems in that it is necessary to remove the optical displacement meter during electrical correction, and a dedicated jig must be used. Another problem is that special measuring equipment is required for mechanical correction. Furthermore, in both cases, there is an economic loss due to having to stop the conveyance line, the work is large-scale and requires a calibration expert, and the equipment becomes larger and more expensive. There are problems such as the possibility that the

In the past, several proposals have been made to solve these problems. For example, JP-A-H], −2
As described in Publication No. 21605 and Japanese Utility Model Application Publication No. 59-4]711-, a reference object to be measured is placed at a plane position approximately at the same height as the target dllll, and this reference object is intermittently measured. There are two methods: one is to measure the thickness of the object to be measured and correct the reference point, and the other is to insert and remove a calibration plate of a predetermined thickness into and out of the pass range of the light beams emitted from each pair of optical displacement meters.

However, these methods are premised on single-point measurement using a C-type gnome, and are difficult to apply, for example, when attempting to perform accurate and precise plate thickness measurement by multi-point measurement.

This is because in the case of multi-point measurement, it is necessary to perform calibration over the entire width of the conveyance line, and the above-mentioned method is a method of performing calibration at one point.

The present invention was made with the aim of solving these problems, and in the case of multi-point measurement, it is possible to easily calibrate the entire width using a small, low-cost device. The purpose of this invention is to provide an automatic sheet thickness measuring device that can measure the thickness of a sheet.

[Means for Solving the Problems] In order to achieve such an object, the present invention provides a pair of sensors arranged above and below a conveyance line that conveys an object to be measured and separated by a predetermined reference distance, A plurality of pairs of optical displacement meters illuminate the object to be measured with a light beam and determine the distance to the object based on the reflected light, and the thickness of the object to be measured is calculated based on the distance measured by the optical displacement wall. A plate thickness calculation means, an absence detection means for detecting that the object to be measured is not being conveyed by the conveyance line, and an L-shaped tip that is bent to form a displacement meter when measuring the thickness of the object to be measured. AI) A calibration plate with a predetermined thickness placed outside the footrest, and a tip positioned at a predetermined position that blocks the light beam emitted from the optical displacement meter when it is detected that the object to be measured is not being transported. A rotation means for rotating the calibration plate so that the calibration plate is rotated, and a left-right movement for moving the optical displacement meter and the calibration plate together in the left and right directions of the conveyance line while the tip of the calibration plate is in a position that blocks the light beam. and a reference distance calculation means for calculating a reference distance based on the output of the optical displacement meter and the thickness of the calibration plate during calibration.

[Function] In the automatic plate thickness measuring device of the present invention, when measuring the plate thickness, the plate thickness of the object to be measured is measured by a plurality of pairs of optical displacement meters and plate thickness calculation means. That is, multi-point measurement is performed.

Further, during calibration, the absence detection means detects that the object to be measured is not being conveyed by the conveyance line, and the rotation means rotates the calibration plate.

The calibration plate is a plate of a predetermined thickness with an L-shaped bend at the tip, and by this rotation, the tip position is set at a position that blocks the light beam emitted from the optical displacement meter.

Further, due to the operation of the left-right moving means, the displacement meter and the calibration plate are integrally moved in the left-right direction of the conveyance line during a period in which the tip of the calibration plate rotates and is in a position that blocks the light beam.

In this state, the reference distance is determined based on the output of the optical displacement meter and the thickness of the calibration plate.

In this way, in the present invention, calibration can be easily and accurately performed over the entire movable width of the optical displacement meter.

[Examples] Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 shows the actual configuration of an automatic plate thickness measuring device according to an embodiment of the present invention. In particular, FIG. 1(a) shows the external appearance of the device as seen from above, and FIG. 1(b) shows the external appearance of the device as seen from the side.

This figure shows a conveyance line 12 that conveys the object to be measured 10 in the direction indicated by the arrow in the figure. The objects 10 to be measured in this figure are steel plates having different thicknesses, widths, etc., and three objects 101, 10-2, ]0-3 are shown in the figure.

In this embodiment, the measuring object 10 to be measured has a thickness of 4 to 60 mm, a width of 800 to 4000 mm,
It has a standard length of 1,500 to 14,000 mm, and is placed at any position on the conveyance line 12 in any orientation.

Further, a pair of upper and lower concave pedestals 14 are provided so as to straddle the transport line 12 . Conveyance line 1 of concave pedestal 14
2, a line sensor 16 is provided on the upstream side, and an optical displacement meter 18 is provided on the downstream side.

A pair of line sensors 16 are movably provided on both the upper and lower concave mounts 14, and detect the positions of both left and right ends of the tip of the object to be measured 10. The detected left and right end positions are used for initial setting of the position of the optical displacement meter 18.

Further, three pairs of optical displacement meters 18 are provided on the concave pedestal 14. This optical displacement meter 18 is a device that measures the thickness of the object 10 to be measured. That is, the optical displacement meter 18
A light beam is irradiated onto the object and the reflected light is captured. moreover,
The distance to the object to be measured 10 is determined based on the captured reflected light, and the distance is used to calculate the plate thickness based on the principle described later.

FIG. 2 shows a more detailed actual configuration of this embodiment as a front view.

In this figure, there are two linear motor rails 20, upper and lower.
is shown. The linear motor rail 20 is a linear motor rail that drives each of the six optical displacement meters 18 in the left and right directions.

Further, the upper three of the optical displacement meters 18 are attached to the pulse stage 22. That is, these three optical displacement meters 18 are driven in the vertical direction by the pulse stage 22.

Furthermore, first and second edge sensors 24 and 26 are attached to two pairs on the left and right sides of the three pairs of optical displacement meters 18. The first edge sensor 24 is used to further finely adjust the position of the optical displacement meter 18, which is initially set according to the output of the line sensor 16. Second edge sensor 26
is used to follow and detect the side edge of the object to be measured 10.

FIG. 3 shows a device configuration related to the calibration of the optical displacement meter 18 in this embodiment. In particular, FIG. 3(a) shows the front of the pair of optical displacement meters 18, and FIG. 3(b) shows the side.

In this figure, a calibration plate 28 is shown which is rotatably arranged at a position shown by a broken line during normal plate thickness measurement and at a position shown by a solid line during calibration. The calibration plate 28 has an L-shaped bend, and the plate thickness at the tip is set to a predetermined thickness that has been certified.

The calibration plate 28 is rotated by a rotary solenoid 30. Further, the calibration plate 28 is provided so as to be movable in the left-right direction of the conveyance line.

FIG. 4 shows the circuit configuration of this embodiment.

In this figure, on the one hand, the plate thickness of the object to be measured 10 is determined based on the output of the optical displacement meter 18, and on the other hand, the linear motor 32 and the pulse stage are determined based on the outputs of the line sensor 16 and the first and second edge sensors 24 and 26. An arithmetic control section 34 that controls 22 is shown. Furthermore, a memory 36 is shown that stores reference distances determined during calibration as a calibration table. In addition, the optical displacement meter 18, the line sensor 16, the first edge sensor 24, and the second edge sensor 26
, the linear motor 32, and the pulse stage 22 are actually plural, but they are omitted in this figure for the sake of simplification.

Next, the operation of this embodiment will be explained.

In this embodiment, first, the object to be measured 10 is placed on the transport line 12. The mounted object 10 is
It is transported by the transport line 12 and reaches below the line sensor 16.

Then, the line sensor 16 detects the light-blocking position caused by the object 10 to be measured. i.e. line sensor]
6 detects the portion where the light beam is blocked by the object to be measured 10 and supplies this to the calculation control section 34 as the left and right end positions of the object to be measured 10 .

The calculation control unit 34 drives and controls the linear motor 32 based on the output of the line sensor 16 to control the position of the optical displacement meter 8. Specifically, a pair of optical displacement meters 18 on both the left and right sides
are moved to both left and right end positions of the object to be measured 10, which are detected as light shielding positions, and placed in the center] pair of optical displacement meters 1
8 is maintained at an intermediate position between the left and right optical displacement meters 18. This initializes the position of the optical displacement meter 18. Since the position detection accuracy of the line sensor 16 is about several tens of mm,
The initial setting accuracy is approximately 1Qmm.

When the object 10 to be measured is further transported and reaches the first edge sensor 24, the position of the optical displacement member 18 is finely adjusted by the first edge sensor 24. The accuracy of the first edge sensor 24 is several mm, for example about ±1.3 mm, and fine adjustment is performed with this accuracy. That is, the calculation control section 34 controls the linear motor 32 according to the output of the first edge sensor 24.

Next, both the left and right ends of the object to be measured]0 are captured by the second edge sensor 26. The second edge sensor 26 outputs a signal that is off when light is blocked and on at other times. At this time, the second
Based on the output of the edge sensor 26, the arithmetic control section 34 controls the near motor 32. That is, the second edge sensor 2
6 is fixed to the optical displacement meter 18, by controlling the second edge sensor 26 so that it is at the on/off boundary, the second edge sensor 26 continues to track and capture both the left and right ends of the object to be measured 10, and The optical displacement meters 18 on both the left and right sides trace a trajectory at a predetermined distance from both the left and right ends of the object to be measured 10, for example.
Detection scanning is performed at a mm pitch.

This detection continues until the optical displacement meter 18 detects an invalid signal.
In other words, the process is continued until the final end of the object to be measured 10 is reached.

1 ] FIG. 5 shows the light beam trajectory of the optical displacement meter 18, and FIG. 6 shows the point (flll
l fixed position) is shown.

In this embodiment, the output of the optical displacement meter 18 related to the trajectory indicated by the three arrow lines in FIG. 5 is continuously collected. After this collection, the calculation control unit 34 determines the fixed position of 71tll and calculates the plate thickness.

More specifically, the calculation control unit 34 controls the first edge sensor 2 after the tip of the object 10 reaches the line sensor]6.
The conveyance speed of the object to be measured 10 is determined from the time taken to reach the speed of 4. Since the distance between the line sensor] 6 and the first edge sensor 24 is determined by design, using this conveyance speed,
The time can be converted into position coordinates with respect to the object to be measured 10. Based on this conversion result, the measurement position is determined.

The measurement position is, for example, 15 m from both the left and right ends of the object to be measured.
m line, 15mm line from both front and back ends, and center line total 6
Determine from the line of the book. In other words, the intersection of these lines is set at the measurement positions P~P.7 Next, for the measurement positions P~P9 set in this way, the optical displacement meter 18 that has been previously collected is The plate thickness calculation based on the output is performed by the calculation control section 34.

FIG. 7 shows the principle of plate thickness measurement in this embodiment.

In this embodiment, the optical displacement meter 1 during plate thickness measurement is
Based on the distance 8 and the 114 force of the paired optical displacement meter 18, the thickness of the object to be measured] 0 can be determined.

First, the facing distance of the optical displacement meter 18 without the object to be measured 10, that is, the reference distance. is determined by design. In addition, in the case of the object to be measured 10 having a thick plate, the distance between the optical displacement meters 8 is set as L3.

Then, the distance L measured by the upper optical displacement meter 18
Distance L2 measured by the lower optical displacement meter 18
Therefore, the plate thickness can be calculated using the following formula.

L=(L+L)-(L1+L2) In this way, in this embodiment, multi-point measurement of the plate thickness is performed based on the measurement positions P□ to P.

Next, the calibration operation according to the feature of the present invention will be explained.

The reference distance is the distance between the optical displacement meters 18. are environmental factors,
Changes due to aging etc. In order to prevent errors from occurring due to this change, calibration using the aforementioned calibration plate 28 is required.

First, the calibration plate 28 whose plate thickness is known is attached to the rotary solenoid 3.
0 and placed at a position between the opposing optical displacement meters 18. The thickness of this calibration plate 28 is ρ. , the distances from the upper and lower optical displacement meters 18 to the calibration plate 28 are Ω and Ω2, respectively.

The distances Ω and g2 are obtained as outputs of the optical displacement meter 18. On the other hand, as shown in FIG. 3, the reference distance Lo
, the following formula % formula % holds true. Therefore, the actual reference distance Lo is determined by the calculation control unit 34 executing the calculation based on the above equation.

In this embodiment, the reference distance LO is calculated for the entire width of the conveyance line 12 by moving each optical displacement meter 18 and the calibration plate 28 in the left-right direction.

That is, the range in which each optical displacement meter 18 can be driven by the linear motor 32 has a relationship as shown in FIG. 8, for example. Drive range 100-1 of three pairs of optical displacement meters 18
．． 100-2.
100-2. Covered by 100-3.

In this embodiment, the reference distance is determined by the calibration plate 28.

This calculation is performed while the optical displacement meter 18 is driven by the linear motor 32. That is, the calculation control unit 34 controls the linear motor 32 to drive the optical displacement meter 18 left and right. For example, each time the optical displacement meter 18 moves by a predetermined amount, the calculation control unit 34 calculates the reference distance based on the outputs ρ and Ω of the optical displacement meter 18. Calculate.

The reference distance Lo obtained in this way is associated with the position coordinates of the optical displacement meter 18, as shown in FIG.
It is stored in the memory 36 as a calibration table.

This calibration table is created for each optical displacement meter 18. The calibration table is referred to when measuring the thickness of the object 10 to be measured.

That is, the calculation control unit 34 obtains the reference distance Lo used in calculating the plate thickness by referring to the calibration table expanded on the memory 36. As a result, the plate thickness is determined based on the recently measured reference distance Lo that matches the position in the width direction of the conveyance line 12.

In this way, according to the present embodiment, the electrical correction and mechanical correction can be performed at once using simple means using the calibration plate 28, and accuracy and reliability can be ensured. In addition, by creating and referring to the calibration table, it becomes possible to offset variations in the optical displacement meter 18 and changes in the reference distance for each position, thereby making it possible to perform more accurate and reliable plate thickness measurements.

[Effects of the Invention] As explained above, according to the present invention, in a multi-point measurement device, calibration including electrical correction and mechanical correction is performed by rotating the calibration plate, and furthermore, the light is adjusted in the left and right direction. Since this calibration is performed while moving the displacement meter and the calibration plate together, it is possible to perform accurate and reliable plate thickness measurement over the entire movable width of the optical displacement meter. Further, the device configuration required for this is simple, and since the calibration is performed automatically, no expert is required, and the calibration can be carried out at low cost.

[Brief explanation of drawings]

FIG. 1 is a schematic external view showing the actual configuration of an automatic plate thickness measuring device according to an embodiment of the present invention, in which FIG. 1(a) is a top view, FIG. 1(b) is a side view, and FIG. 2 is a front view showing a more detailed actual configuration of this embodiment, FIG. 3 is a schematic diagram showing the configuration of the calibration means of this embodiment, and FIG. 3(a) is a front view; Figure (b) is a side view, Figure 4 is a plot diagram showing the circuit configuration of this embodiment, Figure 5 is a diagram showing the locus of the light beam emitted from the optical displacement meter, and Figure 6 is the board. Figure 7 is a diagram showing the thickness measurement position, Figure 7 is a diagram showing the principle of determining plate thickness 6, Figure 8 is a diagram showing the relationship between the movement ranges of each optical displacement meter, and Figure 9 is a calibration table. 10.] 6 Measured object transport line Line sensor Optical displacement meter Calibration plate Rotary solenoid linear motor calculation control unit 1 memory Front view (a) Calibration means 3 Side view (b) Relationship of movement ranges Figure 8 Calibration table Figure 9

Claims (1)

[Scope of Claims] They are arranged in pairs above and below the conveyance line that transports the object to be measured, separated by a predetermined reference distance, and irradiate the object with a light beam to detect the object based on the reflected light. a plurality of pairs of optical displacement meters that calculate the distance between the optical displacement meters, and a plate thickness calculation means that calculates the thickness of the object to be measured based on the distance measured by the optical displacement meters; a calibration plate having a predetermined thickness, the tip of which has an L-shaped bend and whose tip is placed outside the measurement range of the displacement meter when measuring the thickness of the object to be measured; a rotating means for rotating the calibration plate so that the tip thereof is located at a predetermined position that blocks the light beam emitted from the optical displacement meter when it is detected that the optical displacement meter is not being conveyed; A left-right moving means that moves the optical displacement meter and the calibration plate together in the left-right direction of the conveyance line during the period in which the optical displacement meter and the calibration plate are in the blocking position, and a reference distance is determined based on the output of the optical displacement meter and the thickness of the calibration plate during calibration. An automatic plate thickness measuring device comprising a reference distance calculation means.